/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.springcloud.gray.bean.properties.source;

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Stream;

import org.springframework.core.env.MapPropertySource;
import org.springframework.util.Assert;

/**
 * An {@link ConfigurationPropertySource} backed by a {@link Map} and using standard name
 * mapping rules.
 *
 * @author Phillip Webb
 * @author Madhura Bhave
 */
public class MapConfigurationPropertySource
        implements IterableConfigurationPropertySource {

    private final Map<String, Object> source;

    private final IterableConfigurationPropertySource delegate;

    /**
     * Create a new empty {@link MapConfigurationPropertySource} instance.
     */
    public MapConfigurationPropertySource() {
        this(Collections.emptyMap());
    }

    /**
     * Create a new {@link MapConfigurationPropertySource} instance with entries copies
     * from the specified map.
     *
     * @param map the source map
     */
    public MapConfigurationPropertySource(Map<?, ?> map) {
        this.source = new LinkedHashMap<>();
        this.delegate = new SpringIterableConfigurationPropertySource(
                new MapPropertySource("source", this.source),
                DefaultPropertyMapper.INSTANCE);
        putAll(map);
    }

    /**
     * Add all entries from the specified map.
     *
     * @param map the source map
     */
    public void putAll(Map<?, ?> map) {
        Assert.notNull(map, "Map must not be null");
        assertNotReadOnlySystemAttributesMap(map);
        map.forEach(this::put);
    }

    /**
     * Add an individual entry.
     *
     * @param name  the name
     * @param value the value
     */
    public void put(Object name, Object value) {
        this.source.put((name != null) ? name.toString() : null, value);
    }

    @Override
    public Object getUnderlyingSource() {
        return this.source;
    }

    @Override
    public ConfigurationProperty getConfigurationProperty(
            ConfigurationPropertyName name) {
        return this.delegate.getConfigurationProperty(name);
    }

    @Override
    public Iterator<ConfigurationPropertyName> iterator() {
        return this.delegate.iterator();
    }

    @Override
    public Stream<ConfigurationPropertyName> stream() {
        return this.delegate.stream();
    }

    private void assertNotReadOnlySystemAttributesMap(Map<?, ?> map) {
        try {
            map.size();
        } catch (UnsupportedOperationException ex) {
            throw new IllegalArgumentException(
                    "Security restricted maps are not supported", ex);
        }
    }

}
